Lock bolt or nut



Sept. 21, 1948.

D. M. GILMAN LOCK BOLT OR NUT Filed June 15, 1946 Patented Sept. 21,1948 UNITED STATES PATENT OFFICE ooK BOLT on NUT David M. Gilman,Chelsea, Mass. Application June 15, 1946, Serial N math 1 Thisapplication is a continuation-in-part of my application for Lock bolt ornut, filed March 18, 1944, Serial No. 527,083, which was abandoned infavor of the present application. V

This invention relates to lock nuts and bolts and has for an object toprovide a locking element in the form of a split washer which ispermanently retained by the bolt or nut which is locked.

A furthe-robiect is to provide a locking construction which will notdamage the threads of either the bolt or the nut so that each may beused over again as many times as desired. Still another object is toprovide forfrictional holding of the parts where friction is exerted etween the work and the washer as well as between the washer and the nutor bolt.

A further object is to provide simple construction and easy assembly ofthe parts.

Further objects and advantages will appear from a description of certainembodiments of the invention shown in the accompanyingdrawings, in whichI Figure l is an exploded perspective .of a1ocknut with a bolt and thelock washer supported on the bolt.

Figure 21s a central cross section through alock nut, and. a bolt, theshank of the bolt passing through members which are to be securedtogether but before the bolt and nut are tightened up to the work.

Figure 3 is a view similar to Figure 2, but showing the parts when thebolt and nut have been tightened to the work. V

Figure 4 is a detail sectional view on line .44 of Figure 2.

Figure 5 is a sectional view on line 5 5of Figure 3.

Figures 6 and 7 are views similar to Figures 2 and 3, respectively,butshowing the locking wash er as applied to the head of the bolt ratherthan to the nut.

Figures 8 and 9 are views similarto Figuresd and. '7, respectively, butshowing a modification.

Figure 10 is a central cross sectional view through a bolt or screwhaving a lock washer associated therewith and showing a furthermodification.

ing a further modification. V

Referring firstto Figures 1 to 5, at l is shown a nut having a threadedhole 2 for the reception of h the shank 3 of a bolt 4. This bolt 4 maybe of any suitable construction, it being notmodified in any Figure 11is a view similar to Figure 2, butshow 8 Claims. (01. 151-19) ing itsouter walls 6 and l tapered in opposite directions with the maximumdiameter portion 8 somewhat inwardly from the opening face 9 of the nut.These walls 6 and 1 are substantially con-' 1! centric to thethreadedhole 2.

Adapted to be held in the socket 5 is a split washer l0, shown in Figure1 as placed over the shank 3 of the bolt. This washer is of resilientmaterial and is split at one point, the faces ll and I2 ateach side ofthe split portion preferably being normally somewhat spaced apart whenthe washer is in unstressed condition. This washer is provided with atapered face 14 substantially mating thetapered of the recess 5, so thatin order to assemble the.

washer within the socket, it is necessary to spring the washer somewhatclosed in order to reduce its maximum diameter to an extent suflicientto allow it to be passed into the nut recess. After this has once beendone and the washer freed from restraint, it immediately springsoutwardly to an ex:

tent sufficient to prevent accidental removal of the washer from thesocket, the maximum diameter portion of the washer being then too greatto pass through the mouth of the recess.

Preferably the inner face I! of the washer is somewhat larger than themaximum diameter of 35" the bolt shank 3 in order that during use thewasher will never be squeezed together to a pointsuificient so that itsinner .face engages the threads of the bolt. Thus during use there is nopossibility of the bolt threads being marred by engagement with thewasher. The washer is so related to the socket of. the nut that itsouter face zitprojects beyond thenut face so that when thebolt and nutare applied to fasten parts together, as the parts2l and 22 shown inFig? ures 2 and 3, thewasher face engages the face of the work. Thisface may be roughened, as by scoring or knurlingi as shown in Figure 1,to increase the friction between the washer and the work..' Thus whenthe bolt is tightened up onto the work as shown in Figure .3, the splitwasher is crowded back into the recess. The forcing inwardly bythewasher by this tightening action acts through themating inclined facesfiand M of the recess and washer; respectively, to close the washer, itslimit of motion being when the split end faces come together in mutualcontact as shown in Figures 3 and 5, the action being under suflicientlyheavy pressure to provide a frictional grip of the washer against theface of the work and between the washer and the nut, and also producingan axial thrust of the nut threads on the shank of the bolt whichproduces a large frictional drag against loosening of the bolt or thenut when once set up. It is not necessary either" in setting. up. orremov ing the nut to effect any turning motion between the face of thewasher and the work, substantially the entire sliding motion beingbetween" the nut and the washer, there being only the slight relativemotion between the washer and the work caused by closing or opening ofthe washer at the split portion. As this is all. re

stricted to an area smaller than the and race of the nut, no noticeablemarring of the'surface of the work when the nut is in position will beapparent. The work-engaging'face. of. the washer may-be rQughenedas byradial. scoring to. in.- crease. the. frictional. gri on. the work. asshown in. Figure. 1. However, the. bolt and nut may be released byreverse relative turning and be. im mediately ready when; removed. fromthe work. for replacement without. the: first use havin done damage to.either the. bolt or the nut many way, or the work surface: having. been.scored by rotation of a nut or bolthead incontact therewith during thetightenin or. loosening. of. the nut or bolt. They maythus be. used overand over. as desired without loss of. effectiveness or without. marringthe work.

In Figures 6 and. '7- a. modification is shown in.

which. the spring. washer is. applied to. the head of the. bolt ratherthan. to the nut,..anordinary plain nut being used in connection.therewith,. or it may be. threaded directly into. the. work. Asshown in.these. figures, the bolt. head 30 is re cessedi'nwardly'from its face3.! from. which thev threaded. shank 32- extends, this recess. having.tworeversely inclined walls 33 and 3.4.. The. split. Washer- 35 adaptedto. be. seated recesshas. similar reversely tapered; races 31 and. 38and its. maximum diameter portion 39,. when the. washer. is free fromstress, is larger than the mouth 4]] of the. bolt. head recess, so thatthe. washer must. be closed. together somewhat in. order to,- beinserted. into the recess After it. is so inserted and free from stress,it. expands and its maximum diameter then. too-great. to permit. it tobe removed accidentally fromthe recess. This washer extendsoutwardlyfrom the. recessedfaoe as at f! so it bears first against.- the Work. towhich it. is. applied, and asthe nut. and bolt are tightened up, thewasher is; pressed rearwardly into the. recess. as shown in Figure 7-,the washer bein closed. together as. it is forced into theasmall'ei'.diameter. trier portion. of they bolt. head recess, the action beingsubstantially the same as that described inconnection, with Figures. 2.and 3 where. they spring, washer is contained with a recess in the nutrather than. the bolt head. As in the. case of the locking washer in thenut, preferably the inner diameter of this. washer. is. sufflcientlylarge so that at no time does. itbeari against the threads of' the boltvshank, and as has been described. inv connection with the nut lock,preferably the split ends of the washer may be brought: into contactbefore thewasher is driven so far into the recess. as. to. permitthe.bolt. head to? directly contact with the works shown in which, insteadof the outer face of the annular bolt head recess being reverselytapered, the inner face of this recess is so formed and the washer iscorrespondingly shaped. Thus as shown, the outer face of the recess isformed of uniform diameter as at 45, while the inner margin of therecess is provided by reversely inclined faces 46 and 41. The innerperiphery of the split washer is formed with similarly inclinedfaces-.418 and. In unstressed. condition the minimum diameter portion5001 the washer is smaller than the inner diameter of the nut headrecess at the inner face 5i of the bolt head, so that therwasher must besprung open somewhat in order to be inserted into the bolt head recess,aftei' which, when it is allowed to spring somewhat together tounstressed condition, it is held from accidental removal from the recessbyinn-er diameter portion being smaller than the inner diameter of therecess at its mouth. The washer projects outwardly beyond the innerface. of the. bolt head so. that it contacts with the-work when. thebolt is screwed home, as shown in Figure 9, the pressure. against theouter face of the. washer causing it to be pressed backwardlywithin therecess of the bolt headv and to. be. opened; up as. its. inclined face48. rides inwardlyagainst the inclined face 4.6..of the bolt head.

0 in Figure 10 a further. modification is. shownin 6.0. is providedwith. arrecess 6|: in its shank face,

this recess havin a. tapered face 62. The split washer. 63 is, formed.with. a similarly inclined taper face 64 which be'arsagainst the face.62' of the heads The shank 65 of the. bolt or screw is threaded. at 6B.andinwardly or. the threaded portion it. is. of... reduced diameter at67-, while the. minimum inside diameter portion 68 of the split. washerwhen in unconstrainedcondition is smaller. than the, threaded portion'66 of the. shank and larger than the reduced diameter portion 61 ofthis. shanln. Thus. the washer. may be. sprung open mnastic tobelpas'sedlojver the.- threaded portion of; the. shank. andthen whensreaches the small diameter portion and is freed, it springs sufficientlyfar closed as to prevent accidental removalthereofl. When the bolt orscrew so formed is screwed home, the. pressure of. the. work against theinner face of the washer forcing it. further into. the recess, causesthe reaction of the inclined faces 64 and 62 to tend to close the washerto- Eetherand results in a. heavy frictional locking efi'ec't betweenthese inclined faces accompanied by an. end thrust. on the shank whichserves to lock the. bolt ors'crew against undesired looseningj', Here,again, however, by turning the bolt or screw the" reverse direction, itmay be freed.

pendi'cular to the axis of the nut instead of being.

tapered as. is the face 'lshown in Figures 2 and 3, and the split washerlllll is. similarly contoured.

m The action, however, is the same, the washer [.00

beiiig. capable. of sufficient deformation. to pass the inner margin. ofthe-shoulder. for insertion into the recess. or withdrawal. therefrom.

. In? all the constructions shown, one of the parts,

In. Eigures 8;- and. 9, a further. modification is 7.5a either thenutorthe bolt, is provided with a. re-

cess to receive the split washer, the recesshav ing an inclined face,and the part ha ving an opposed shoulder which is of a diametereitherinthe washer being provided with a tapered face substantiallymating the taper of the recess and being of a length to project out ofthe recess sufilciently to be engaged with the face of the work to whichthe bolt and nut is applied.

From the foregoing description of certain embodiments of this invention,it should be evident to those skilled in the art that various changes.

and modifications might be made without departing from the spirit orscope of this invention.

I claim:

1. In combination, a threaded member adapted to cooperate with a matingthreaded member for fastening purposes, one of said members having arecess in one face having oppositely tapered wall portions concentricwith the axis of the threads and merging in a maximum diameter portion,and a split spring washer seated in said recess and havin tapered facesreversely positioned with respect to the tapered faces of said recess,the maximum diameter portion of said washer when in unstressed conditionand with its split ends spaced apart being greater than the face openingof said recess, whereby said washer must be pressed toward split endclosed condition to be inserted into said recess and after bein soinserted and freed from pressure is retained therein, said washerprojecting outwardly beyond said member to be engaged by work secured bysaid member and said cooperating threaded member and forced inwardly andwith its split ends forced toward each other as said members aretightened against the work.

2. In combination, a threaded member adapted to cooperate with a matingthreaded member for fastening purposes, said member having a recess inone face having oppositely tapered wall portions concentric with theaxis of the threads and merging in a maximum diameter portion, and asplit spring washer seated in said recess and havin tapered facesreversely positioned with respect to the tapered faces of said recess,the maximum diameter portion of said washer when in unstressed conditionand with its split ends spaced apart being greater than the face openingof said recess, whereby said washer must be pressed toward split endclosed condition to be inserted into said recess and after being soinserted and freed from pressure is retained therein, said Washerprojecting outwardly beyond said member to be engaged by work secured bysaid member and said cooperating threaded member and forced inwardly andwith its split ends forced toward each other as said members aretightened against the Work, the inner bore of said washer being oflarger diameter than the threaded portion of said member even when saidsplit ends are brought into mutual contact.

3. In combination, a nut threaded for the reception of a bolt, said nuthaving a recess in one end face having oppositely tapered wall portionsconcentric with the axis of the threads and merging in a maximumdiameter portion, and a split spring washer seated in said recess andhaving tapered faces reversely positioned with re spect to the taperedfaces of said recess, the maximum diameter portion of said washer inunstressed condition and with its split ends spaced apart being greaterthan the face opening of 6,. said recess, wherebysaid washer must bepressed toward split closed conditionto be inserted into said recess andafter being so inserted is retained therein, said washer projectingoutwardly beyond said nutend to be engaged by work secured by said nutand bolt and forced inwardly and with its split ends toward each otheras said nut is tightened on said bolt. i i

4. In combination,a bolt having a head and threaded shank, said 'headhaving an annular recess inits shank face, the outermargin of saidrecess h'aving oppositely tapered wall portions substantially concentricto the axis of said shank and merging in a maximum" diameter portion,and a split springwasher seated in said recess and having tapered facesreversely positioned with respect to the tapered faces of said recess,the maximum diameter portion of said washer in un-stressed condition andwith its split ends spaced apart being greater than the face opening ofsaid recess whereby said washer must be pressed toward split closedcondition to be inserted into said recess and after so inserted andfreed is retained therein, said washer projecting outwardly beyond saidhead face to be engaged by work secured by said bolt and forced inwardlyand with its split ends toward each other as sai bolt is tightenedagainst the work.

5. In combination, a bolt having a head and a threaded shank, said headhaving an annular recess in its shank face, one side wall of said recessbeing tapered in opposite directions, a split spring washer seated insaid recess and having its wall facing said tapered wall matinglytapered, the

extreme free diameter of said washer tapered faces being sufficientldifferent and in the proper sense from that of the mouth of said recessat said tapered faces that said washer must be sprung to be insertedinto said recess and is thereafter when freed retained therein againstaccidental removal, said washer projecting out of said recess thereby toengage the face of work through which said bolt may extend in service.

6. In combination, a threaded fastener having a head and a threadedshank, said head having an annular recess in its shank face, said recesshaving a tapered wall portion concentric to the axis of said shank, anda, split spring washer seated in said recess and having a tapered facereversely positioned with respect to the tapered face of said recess,said washer projecting outwardly of said head to be engaged by worksecured by said fastener and with its split ends forced toward eachother as said fastener is tightened to the work, said fastener andwasher having parts cooperating when said washer is in unstressedcondition to obstruct removal of said washer from said fastener, saidwasher having a bore through which said shank extends of sufficientdiameter for said washer to be free from said shank when said split endsare in contact with each other.

'7. In combination with a threaded member, a mating threaded membercooperating therewith for fastening purposes, one of said members havinga recess in one face having a tapered wall portion and an opposedannular shoulder, and a split washer seated in said recess andprojecting therefrom, said washer having a face tapered to substantiallmate the tapered face of said recess, said shoulder being of a diameterto permit removal from and insertion of said washer into said recesstherepast only on deformation of said washer from normal condition, saidwasher having a bore through which one of said, threaded members extendsofsuffieient diameter tube free from said one threaded member when thesplit portion of said. washer is closed.

8. In combinationwith a threaded member, a

tapered face of said recess, and positioned between said tapered face ofsaid recessjancl said shoulder portion, said'shoulider portion being ofsuch-size relative to said washer as to prevent removal of said 'washerpast said shoulder por tion when said washer is in unstressed condition,

82 but permitting such removal when said washer is sprung suflicientlyout of such condition, said washer having a bore through which one ofsaid threaded members extends of suflicient diameter to befreefrom saidone threaded member when the split portion of. said washer is closed.

' DAVID: M. GILMAN.

REFERENCES CITED The following references are of record in the file ofthis patent:

FOREIGN PATENTSv Country Date Switzerland June 6, 1919 Number

